Structure of Globular Clusters

Abstract

There was a time, more than a century ago, when Astronomy & Astrophysics was not a European Journal yet, but still an American one. In its Vol. XII, Bailey (1893) published, from photographic observations of two globular clusters (GCs), ω Centauri and 47 Tucanae, what were probably the first extensive star counts, which represent the oldest observational constraint for the study of the structure of GCs. Bailey’s counts, together with some new material concerning other clusters were used by Pickering (1897) in the first important comparisons between observed and theoretical profiles in order to study the radial distribution of stars in clusters.